Australians have been warned that their freedoms might have to be restricted for the sake of national security, as the government prepares to introduce counter-terrorism laws to crack down on Australians fighting for militant or terrorist groups.

The Prime Minister told the House of Representatives that laws would include the creation of an offence for travelling to certain areas, such as Raqqa in Syria, without good reason.

"My unambiguous message to all Australians who fight with terrorist groups is that you will be arrested, prosecuted and jailed for a very long time; and that our laws are being changed to make it easier to keep potential terrorists off our streets," Mr Abbott said .

"The only safe place for those who have been brutalised and militarised by fighting with terrorists is inside a maximum security prison."

The opposition is likely to support the government's new counter-terror legislation but in recent days concerns have emerged about the onus of proof being reversed for Australians travelling overseas to areas the government of the day considers a terrorism hot spot.

Opposition Leader Bill Shorten said Labor would carefully consider the government's legislation to ensure it did not damage the very liberties it was seeking to protect from any terrorist threat.

"We will give legislation that addresses the problem of these foreign fighters the careful consideration it deserves," Mr Shorten said.

"Labor believes that our security agencies and national institutions should have the powers and resources they need to keep Australians safe from the threat of terrorism.

"But we also believe in safeguarding fundamental democratic freedoms.

"We must ensure that in legislating to protect our national security, the Parliament is careful not damage the very qualities and liberties that we are seeking to defend from terrorist threat."

Mr Abbott will be in New York later this week for special United Nations talks on the escalating military situation in Iraq and the international response to the Islamic State, also known as ISIL.

There has been a security crackdown at Parliament House since last week's raids and Mr Abbott warned that would mean more "armed police, fewer points of access, and more scrutiny of parliamentary passes".

"They will mean slightly more inconvenience but considerably more protection for everyone involved in our national government," Mr Abbott said.